Appealing Numbers - Ivars Peterson (MathTrek)
A short history of amicable numbers - pairs in which each number is the sum of the proper divisors of the other. The smallest such pair is 220 and 284. The number 220 is evenly divisible by 1, 2, 4, 5, 10, 11, 20, 22, 44, 55, and 110, which add up to
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Arithmagic - Ivars Peterson (MathTrek)
Arthur T. Benjamin eschews the usual trappings of the magician's trade. Calling himself a mathemagician, he astonishes audiences with amazing feats of mental arithmetic. Behind the scenes, he reveals how you, too, can look like a genius without really
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A Bibliography of Bernoulli Numbers - Karl Dilcher
A bibliography of Bernoulli numbers by Karl Dilcher and Ilja Sh. Slavutskii. The Bernoulli numbers are among the most interesting and important number sequences in mathematics. They are particularly important in number theory, especially in
connection
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BrainBashers - Kevin N. Stone
A collection of logic, language and math puzzles, in a choice of easy/medium/hard. Rate the puzzles; show their answers. Logic puzzles include Einstein's Puzzle. Play games of strategy, such as "Four in a Row" (also known as "Connect Four") or games based
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CalculationRankings - Youri Lieberton
Arithmetic problems to solve or number sequences to complete as a stopwatch counts down. Play the games to compare high scores against other speedy problem solvers; take the timed tests to see correct answers after submission.
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Cubes of Perfection - Ivars Peterson (MathTrek)
...Six is the smallest perfect number. Twenty-eight comes next. Its proper divisors are 1, 2, 4, 7, and 14, and the sum of those divisors is 28. Incidentally, if the sum works out to be less than the number itself, the number is said to be defective
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David Sumner's Home Page - David Sumner
Study guides, exams, quizzes, problem sets, exam review materials, utilities, programs and simulations, syllabi, and other materials for courses such as calculus, sequences and series, graph theory, number theory and cryptography, and probability. The
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Edutest: Online Assessment Resource
Assessment testing based on nationally recognized standards in Math and Language Arts for grades 2-8. Scoring is instant and both parents and teachers can review the tests and the correct answers with their students. The site has some information for
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Excel Math - AnsMar Publishers, Inc.
Excel Math is a mathematics curriculum for Kindergarten through Sixth grade students. Students are repeatedly given practice in the use of the concepts, following their introduction, so that they retain them and develop a solid foundation on which to
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Four Numerical Triangles in Nexus - Len Smiley
Three well-known combinatorial number triangles are tightly related to each other as coefficients in transforms of a seminal sequence of exponential generating functions (for n^{n+m}). A fourth triangle is a part of the picture in much the same way that
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Friedman Numbers - Erich Friedman
A Friedman number is a number that can be written in some non-trivial way using its digits, the operations + - * / ^ and concatenation of digits. For example, 25 and 126 are Friedman numbers, since 25 = 5^2, and 126 = 6 * 21. Page includes a list of all
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Home Run Numbers - Ivars Peterson (MathTrek)
The integers 61 and 62 have been very much in the news this summer. On the major-league baseball front, Mark McGwire hit his 62nd home run on Sept. 8, and Sammy Sosa matched that total on Sept. 13, surpassing the record of 61 home runs in a season held
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IXL Learning
IXL provides free online practice, organized by grade levels K-8 and aligned to state standards. Choose one math skill from among the hundreds offered, and submit your answer. Respond incorrectly, and click on the "explanation" button to learn more; get
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Juggling by Design - Ivars Peterson (MathTrek)
The earliest known depiction of juggling is on the wall of an Egyptian tomb nearly 4,000 years old. The painting shows a woman keeping three balls aloft. It's only in the last decade or so, however, that juggling has become the subject of serious mathematical
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Keith Numbers - Mike Keith
A Keith number is an n-digit integer N with the following property: If a Fibonacci-like sequence (in which each term in the sequence is the sum of the n previous terms) is formed, with the first n terms being the decimal digits of the number N, then N
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License Codes - Ivars Peterson (MathTrek)
Some states use complicated schemes for establishing driver's license identification numbers. The numbers may include check digits to detect errors or fraud, or they may encode such personal data as the month and date of birth, year of birth, and sex.
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LSL Math Traits - Gary T. Leavens
A guide to an archive of mathematical traits written in the Larch Shared Language (LSL), constituting a small LSL handbook. The traits do not duplicate the traits in Guttag and Horning's book, but add to them. Real numbers; Polynomial Functions and Polynomials;
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Marc Chamberland
A mathematician at Grinnell College interested in differential equations and dynamical systems. Resources for the 3x + 1 problem and the Jacobian Conjecture include papers to download in PostScript format and information and proceedings for related conferences.
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Mastering Mastermind - Ivars Peterson (MathTrek)
"Games offer wonderful playing fields for developing mathematical problem-solving skills. For Mathew Mitchell of the School of Education at the University of San Francisco, the preferred training ground is a classic game called Mastermind. "Students young
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The Mathman - Don Cohen
Materials for sale for K-12 students, teachers and parents; pre-calculus. Materials include Get Ready for Calculus (Calculus By and For Young People book, CD-ROM, worksheet book, videotapes and map) and Changing Shapes with Matrices. Patterns, visualization,
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Medieval Harmony - Ivars Peterson (MathTrek)
Harmonic numbers. The history of mathematics contains many gems of mathematical reasoning and thought. At a Mathematical Sciences Research Institute meeting last October, number theorist Hendrik W. Lenstra Jr. of the University of California at Berkeley
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A Nameless Number - Len Smiley
Triangle-free polygon dissections are a variant of the dissection questions of Catalan, Schroeder, and others: In a convex (n+2)-gon with n+2 labeled nodes, what is a(n), the number of ways of drawing non-intersecting diagonals so that no triangles are
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